For the operation of a hybrid drive system, the distribution of load between different drive units, or, in the case of an internal combustion engine as one of the drive units, its state of activation (start/stop operation), is permanently ascertained. The load distribution can for example be determined using an optimization method continuously carried out online, i.e., in the motor vehicle. Generally, the optimization method is optimized with regard to a minimization of an energy use or emissions output.
In particular, during operation of an internal combustion engine, it may be necessary in some driving situations, and/or with a particular frequency, to carry out special functions that require the assumption of special operating states. The special functions can include diagnostic functions, calibration functions, or component protection functions, and the like. When there are requests for the carrying out of special functions, such as for a carrying out of a catalytic converter heating operation or a sensor diagnosis, generally these have to be assumed within a particular period of time after the request is made.
It is true that for some requested operating states, such as a catalytic converter heating operation, possibilities are known for adapting the operation of a hybrid drive system, but a general inclusion of special function requests in the general method that provides an optimization of the energy usage for the determination of the load distribution has up to now not been possible.
German Patent Application No. DE 198 50 586 A1 describes a method for operating an internal combustion engine in which fuel is injected into a combustion chamber in at least two operating modes, and in which a changeover takes place between the operating modes as a function of a target operating mode, the target operating mode being ascertained from a plurality of operating mode requests. In particular, each of the operating mode requests can be assigned a priority, and the ascertaining of the target operating mode can be carried out as a function of the priorities of the operating mode requests.
German Patent Application No. DE 10 2005 018 270 A1 describes a method for controlling an internal combustion engine, the internal combustion engine being operated in an operating mode that is determined by an operating mode coordinator that selects, from among operating mode requests, the request having the highest priority that is not forbidden by other operating mode requests.
German Patent Application No. DE 10 2011 078 484 A1 describes a system for controlling a combustion state of an internal combustion engine, the system having a control unit that is set up to carry out a prioritization of requests for operating states on the basis of the present state of combustion, and to process the accordingly received requests in the sequence of their priorities.